Automated sewing device

ABSTRACT

An automated sewing device for sewing at least one base material with two curved corner portions, which includes a sewing machine, a base guide plate and a movable guide plate. The movable guide plate has three guide rollers, each being respectively disposed at the apexes of an equilateral triangle, in the reverse side thereof, and the movable guide plate is formed with a plurality of guide grooves in such a pattern that describes three loci respectively of the three guide rollers required to cause proper displacements of the movable guide plate for guiding at least one side of the base material including the two curved corner portions in a direction to the sewing needle of the sewing machine. With such arrangement, the base material is automatically fed and sewn by the feeding and sewing force of the sewing machine, insuring to precisely sew each of the two curved corner portions of base material along the curvature thereof.

BACKGROUND OF INVENTION

1. Field of the Invention

The present invention relates to an automated sewing device for sewingautomatically base cloth or cover materials together into a trim coverassembly used on an automotive seat. More specifically, the presentinvention is directed to an automated sewing device capable of sewingtogether, automatically, particular shaped base cover materials havingcurved portions into one trim cover assembly, wherein the trim coverassembly is of a three-layer lamination type comprising a top covermember, a slab foam wadding member (made of urethane foam material) anda back cloth (or wadding cover).

2. Description of Prior Art

In general, a seat back or seat cushion forming an automotive seat isformed substantially in a rectangular shape, including a pair of forwardcurved or arcuate corners. In most cases, each of those two curved orarcuate forward corners has approx. 10 cm radius of curvature.

Thus, a process in the seat assemblage involves the steps of preparingthe following two typical base cover materials: a central-cover-sectionbase cover material having a pair of forward curved corner portions,each having the same 10-cm radius of curvature with the above-noted one,and a substantially U-shaped side-cover-section base cover materialwhich includes a pair of forward curved corner portions, each having aradius of curvature close to 10 cm, in order to form a particular trimcover assembly covering the foregoing kind of seat back or seat cushion.Accordingly, the central-cover-section base cover material is definedherein as a cenral cover section of a resulting seat cover assembly forcovering the main upper surface of seat back or seat cushion, whereasthe side-cover-section base cover material is defined herein as anotherperipheral cover section of the resulting seat cover assembly forcovering lateral side surfaces of seat back or seat cushion.

Coventionally, this sort of trim cover assembly has been formedmanually, using an ordinary sewing machine. In the sewing operation, anoperator needs to laminate one sewing end portion of theside-cover-section base cover material, at a given margin (e.g. 10 mm),upon the mating sewing end portion of the central-cover-section basecover material, to provide a sewing margin. Then, along the sewingmargin, the operator uses his or her eyes and hands to manually guidethe two base cover materials towards the sewing needle of sewingmachine, while moving one of the two base cover material, i.e. thecentral-cover-section base cover material, in appropriate directions, sothat the mated ends of both two base cover materials may be sewntogether along a predetermined outer configuration of seat cushion orseat back. But, this manual process requires a long-experienced, highexpertise on the operator's part and does not guarantee to form allsatisfied sewn trim cover assembly in constant way.

Recently, an automated sewing machine has been proposed in an attempt tosolve the foregoing problems, such as the one disclosed in the JapaneseU.M. Laid-Open Pub. No. 54-72966. According thereto, an automated sewingmachine is disclosed, which is capable of sewing automatically the endof three layer lamination of base cover materials. The sewing machineincludes a lower guide plate on which the three base cover materials areplaced, and an upper guide plate having, provided thereon, a guide railextending along the peripheral end thereof, the guide rail having aguide groove defined therein. The guide plate is slidably movable on thetable of sewing machine. The sewing machine further includes a guideroller disposed just above the sewing needle, which is rotatably fittedin such guide groove on the upper guide plate. With this structure, thethree base materials are sandwiched securely between the upper and lowerguide plates, and then operation of the sewing machine causes thethus-secured base materials to be automatically fed towards the sewingneedle, while simultaneously causing movement of both guide plates alongthe guide rail, whereby the sewing is effected to and along theperipheral end of the base materials.

However, in this prior art structure, the two base cover materials areguided by the two points; namely, the feeder of sewing machine and theengagement point where the guide roller is rotatably engaged in theguide rail. This certainly permits precise locating of the base covermaterials with respect to the sewing needled, but when sewing a curvedportion of the base materials, a simple guide roller and rail mechanismdoes not precisely guide the curved portions of base materials towardthe sewing needle in a direction of tangent touching on the curvature ofsuch curved portions. Consequently, the curved portions of base covermaterials are not sewn correctly and the resulting sewn cover membershows a poor seam at its curved portion or corner.

SUMMARY OF THE INVENTION

In view of the above-stated drawbacks, it is therefore a primary purposeof the present invention to provide an improved automated sewing devicewhich permits a base material with two curved corner portions to be sewnalong the peripheral sides thereof, automatically, with precision.

To attain such purpose, the present invention basically comprises:

a sewing machine including a sewing needle and feeding member;

a movable guide means having a shape generally similar to that of thebase material, upon which movable guide means, the base material is tobe secured;

the movable guide means being provided, on a reverse side thereof, witha first guide roller, a second guide roller and a third guide roller, insuch a manner that the first and second guide rollers are respectivelydisposed at one point corresponding to a center of curvature of onecurved corner portion of the base material and at another pointcorresponding to a center of curvature of another curved corner portionof the same base material, and further that all the first, second andthird guide rollers are disposed at three apexes of an equilateraltriangle, respectively; and

a base guide plate means in which a plurality of guide grooves areformed in such a pattern that describes three loci respectively of thefirst, second and third guide rollers required to cause properdisplacements of the movable guide means for guiding at least one sideof the base material including the two curved corner portions in adirection to the sewing needle of the sewing machine, wherein, upon thebase guide plate, the movable guide means is movably mounted, with thefirst, second and third guide rollers being slidably fitted in the guidegrooves.

Accordingly, the foregoing at least one side of base material can beautomatically fed and sewn by the sewing machine, with the movable guidemeans being displaced under guidance of the first, second and thirdguide rollers which follow the respective three loci. Hence, the basematerial is stably supported at three points in such triangular guideroller arrangement, thereby insuring to sew those particular curvedcorner portions of the base material in the tangential direction, with agreat precision. Further, there is no need to prepare a special feederfor feeding both moveable guide means and base material, whichcontributes to a low-cost and simple structure of the present sewingdevice.

Another purpose of the present invention is to facilitate the change ofdirection of the first and second guide rollers at their respectiveacutely curved groove areas in the guide grooves.

For that purpose, in accordance with the present invention, there areprovided first and second auxiliary guide roller means, each preferablycomprising an auxiliary guide roller and a cylinder, wherein operationof the cylinder causes movement of the guide roller to push one of thefirst and second guide rollers at its acutely curved groove areas,helping thus to allow the same to smoothly change its direction there.Preferably, to actuate each of those two auxiliary guide roller meansautomatically, a sensor means may be provided at proper points in theguide groove in which the third guide roller follows at the point oftime when one of the first and second guide rollers follows its acutelycurved groove area.

Preferably, in addition to such two auxiliary guide roller means, aspeed control means may be arranged in the present sewing device, suchas to automatically decrease the sewing or feeding speed of sewingmachine during the time when one of the first and second guide rollersreaches its acutely curved groove area, or when one of the curved cornerportions of base material is sewn.

Preferably, the guide grooves may be of a pattern which includesgenerally straight groove areas, curved groove areas and generallycircular groove areas, which are formed in conformity with the threeloci respectively of said first, second and third guide rollers requiredto cause proper displacements of the movable guide means for guidingsaid at least one side of the base material including the first andsecond curved corner portions in a direction to the sewing needle ofsewing machine, such that the first, second and third guide rollers mayfollow the generally straight groove areas to cause a generally straightside portion of the base material to be sewn by the sewing needle alonga sewing direction thereof, and then one of the first and second guiderollers may follow the curved groove areas in cooperation with the thirdguide roller following the generally circular groove areas so as tocause one of the two curved corner portions of the base material to besewn by the sewing needle along a curvature thereof, after which,another of the first and second guide rollers may follow the curvedgroove areas in cooperation with the third guide roller following thegenerally circular groove areas so as to cause another of the two cornerportions of the base material to be sewn by the sewing needle along acurvature thereof.

More preferably, the foregoing guide groove pattern may be so arrangedthat both curved and generally circular groove areas are definedcentrally of the movable guide means, such that the circular grooveareas are disposed inwardly of the curved groove areas, and the straightgroove areas are defined on opposite sides of those curved and generallycircular groove areas, so that the first, second and third guide rollersmay follow the straight groove areas along their respective locuses tocause sewing of the generally straight side portion of the basematerial, at each of sewing start and sewing end points on the movableguide means, and that the first and second guide rollers may follow thecurved groove areas along their respective said loci, while the thirdguide roller may follow the generally circular groove areas along thelocus thereof, without interference among those three guide rollers, tocause each of the first and second curved corner portions of the basematerial to be sewn along the curvature thereof by the sewing needle.

Yet more preferably, in the foregoing patterns of guide grooves, thegenerally straight groove areas include a common groove portion disposednear the sewing needle, while the curved groove areas include first andsecond curved groove portions which are distant from the sewing needleand disposed generally in a symmetrical relation with each otherrelative to the sewing needle, the arrangement of those common, firstand second curved groove portions being such that when sewing the firstcurved corner portion of the base material, the second and third guiderollers are displaced in a generally arcuate way with respect to thefirst guide roller being positioned at the common groove portion,thereby causing the first curved corner portion to be sewn by the sewingneedle in a direction of tangent touching on the curvature of the firstcurved corner portion, and that when sewing the second curved cornerportion of the base material, the first and third guide rollers are alsodisplaced in a generally arcuate way with respect to the second guideroller being positioned at the common groove portion, thereby causingthe second curved corner portion to be sewn by said sewing needle in adirection of tangent touching on the curvature of the second curvedcorner portion.

In one aspect of the invention, the movable guide means is provided, atan upper surface thereof, with a securing means for locating andremovably securing the base material upon the movable guide means, andthe securing means comprises a peripheral securing element disposedalong a peripheral side of the movable guide means, and a securingneedle disposed generally centrally of the movable guide means.

In another aspect of the invention, the movable guide means is a movableguide plate formed in a shape generally similar to that of said basematerial, which is provided, at a reverse surface thereof, with thefirst, second and third guide rollers, and further provided, at an uppersurface thereof, with a securing means for securing the base materialthereon, said movable guide plate having at least one side whichincludes two curved corner portions generally similar to those of suchat least one side of said base material, wherein such at least one sideof the base material is to be located and secured on the foregoing atleast one side of said movable guide plate via the securing means, andwherein the base guide plate means includes a location wall erected atone end side thereof, the location wall being formed in a shapegenerally similar to the foregoing at least one side of the movableguide plate, so that the movable guide plate may be set on the baseguide plate in reference to the location wall and thereafter, the basematerial may be precisely located in a given position upon the baseguide plate by bringing said at least one side of the base material tocontact and alignment with the location wall.

In yet another aspect of the invention, a stationary guide plate isprovided above the movable guide means, so that another base materialmay be introduced on the stationary guide plate towards the sewingmachine, and then a part of such another base material may be sewn withand along the foregoing at least one side of said first base materialwhich is secured on said movable guide means.

Other various features and advantages of the invention will becomeapparent from reading of descriptions hereinafter, with reference to thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic perspective view of an automated sewing device inaccordance with the present invention;

FIG. 2 is a schematic perspective view of first and second base covermaterials to be sewn together by the automated sewing device;

FIG. 3 is a plan view of a movable guide plate provided in the automatedsewing device;

FIG. 4 is a sectional view taken along the line IV--IV in the FIG. 4;

FIG. 5 is a schematic plan view showing the movable guide plate to beset on a base guide plate in a cover setting/sewing terminal section ofthe automated sewing device;

FIG. 6 is a schematic plan view showing the first cover material to besecured on the movable guide plate set on the base guide plate in thecover setting/sewing terminal section;

FIG. 7 is a sectional view taken along the line VII--VII in the FIG. 5;

FIG. 8 is a partly broken, schematic plan view showing the base guideplate;

FIG. 9 is a partly broken sectional view of a part of the base guideplate and an auxiliary roller device;

FIG. 10 is a partly broken sectional view of the same part of the baseguide plate as in the FIG. 9 which is viewed from a different sidethereof;

FIG. 11 is a schematic plan view indicating a first guide groove in theguide groove pattern;

FIG. 12 is a schematic plan view indicating a second guide groove in theguide groove pattern;

FIG. 13 is a schematic plan view indicating a third guide groove in theguide groove pattern;

FIG. 14 is a diagram showing the displacements of both movable guideplate and three guide rollers for sewing one curved corner portion ofthe two cover materials;

FIG. 15 is a diagram showing the displacements of both movable guideplate and three guide rollers for sewing a forward side of the two covermaterials;

FIG. 16 is a diagram showing the displacements of both movable guideplate and three guide rollers for sewing another curved corner portionof the two cover materials; and

FIG. 17 is a schematic perspective of a trim cover assembly produced bythe automated sewing device.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT OF INVENTION

Referring to FIG. 1, there is generally shown an automated sewing devicein accordance with the present invention.

Designation (M) denotes a main sewing machine which is electricallyconnected with a computerized control section (M1), and thus, the mainsewing machine (M) may be driven and stopped through operation of thecontrol section (M1).

Fixedly mounted on the table (T) of the sewing machine (M) is a guidebase plate (2) which has a particular pattern of guide grooves formed inthe upper surface thereof, the grooves being basically comprised of afirst guide groove (21), a second guide groove (22) and a third guidegroove (23), as can be seen from FIG. 1, which will however be describedin details later.

A movable guide plate (1) is movably mounted on the guide base plate(2). As will be described later, the movable guide plate (1) is providedon its reverse side with three guide rollers (11)(12)(13) which arerespectively supported rotatably by disc support brackets (11A) (12A)(13A) (See FIGS. 3 and 4), in a manner that guide rollers (11)(12) (13)are respectively rotatably fitted in the foregoing three guide grooves(21)(23)(22). Hence, the guide plate (1) may be moved in predetermineddirections along the three guide grooves (21)(23)(22), which will alsobe explained in greater details later.

Designation (3) denotes a stationary guide plate disposed at a levelabove the movable guide plate (2) set on the guide base plate (1). Thestationary guide plate (3) is provided with an auxiliary guide device(3A) which includes a guide introductory plate (3A-2), a guide opening(3A-2a) formed in the guide introductory plate (3A-2), and a roller(3A-1) movable vertically to permit its contact with the surface ofstationary guide plate (3) through the guide opening (3A-2a).

Generally designated by (5) and (6) is a device for fixing a decorativebeading to a sewn line which is formed by using the present sewingmachine to sew together base cover materials mentioned below. In brief,the core wire (5a) set in a basket (5) is fed with a tape of beadingcover (5a) by means of rotary feeding device (6) towards the sewingneedle (100) of main sewing machine (M), so that a unit of resultingcombined core wire (5a) and beading cover (6a) is sewn, as decorativebeading, with the undermentioned two base cover materials, at one time,along a seam. But, this is not the principal part of the presentinvention and any further explanation thereon is deleted for the sake ofsimplicity in description.

The illustrated sewing device is designed to automatically sew togethertwo typical base cover materials into one trim cover assembly forcovering a seat cushion of an automotive seat. But, the presentinvention is not limited thereto, and the sewing device may be used forsewing the peripheral end portions of one base cover material. Here, thetwo typical base cover materials refer to a central-cover-section covermaterial (4) and a side-cover-section cover material (7), respectively,as shown in FIG. 2. As previously stated in the description of priorart, the central-cover-section and side-cover-section cover materials(4)(7) are for covering the main upper surface of seat cushion and thelateral vertical surface of the same, respectively. (see FIG. 17)

Hereinafter, the central-cover-section base cover material (4) shall bereferred to as a "first cover material", and the side-cover-section basecover material (7) be referred to as a "second cover material".

As in FIG. 2, the first cover material (4) is of a generally squareshape, having a pair of forward curved or arcuate corner portions(41)(42) formed in the forward side thereof. On the other hand, thesecond cover material (7) is of a generally U-shaped configuration,extending at a length equal to that of peripheral end portion of thefirst cover material, excepting the backward side of the same. Each ofsuch two forward curved corner portions (41)(42) has a same radius ofcurvature (R1) (e.g. 10 cm), and thus the two curved corner portions ofthe second cover material (7) each has a slightly greater radius ofcurvature than that (R1) of the corresponding corner portions (41)(42)of first cover material (4).

Designations (40)(70) in FIG. 2 stand for a seam imaginarily indicatedin both two cover materials (4)(7) for better understanding, butpractically, it should be understood that the seam (40, 70) is one seamcreated by one sewing yarn of the sewing machine (M) which connects thetwo cover materials (4)(7) together, and therefore indicative of asewing line along which the inward peripheral end of second covermaterial (7) is to be sewn and connected with the outward end of firstcover material (4) through operation of the present sewing device. Also,designations (40A)(40B) respectively denote a sewing start point and asewing end point, in the first cover material (4), whereas designations(70A)(70B) respectively denote sewing start and sewing end points in thesecond cover material (7).

FIGS. 3 and 4 illustrate the movable guide plate (1). This movable guideplate (1) is formed from a synthetic resin material in the shown shapesimilar to the outer shape of the foregoing first cover material (4),but smaller than the latter by a proper sewing margin (i.e. a margin toseam). This can be understood by comparing the phantom line of firstcover material (4) with the outermost solid line of movable guide plate(1) in FIG. 3. The movable guide plate (1) has a pair of forward curved(or arcuate) corner portions (101)(102), each corresponding to therespective foregoing two curved corner portions (41)(42) of first covermaterial (4). But, for giving the sewing margin, each of the two curvedcorner portions (101) (102) of the movable guide plate (1) should have aslightly smaller radius of curvature (R) than that (R1) of the twocurved corner portions (41) (42) of first cover material (4), asindicated in FIG. 3.

As seen in FIG. 1, the present sewing device is divided into a coversetting/sewing terminal section (AS) and a sewing start section (BS),both of which lies generally symmetrically relative to the sewingmachine (M). As will be described later, the former section (AS) serves,at the initial stage, as a cover locating place where the first covermaterial (4) is to be located precisely and secured on the movable guideplate (1) at an initial operation stage, and further serves, at a finalstage, as a sewing end point where the sewing is to be completed and themovable guide plate (1) be stopped. The latter section (BS) is a sewingstart place where the movable guide plate (1) with the first covermaterial (4) secured thereon is to be set and subject to sewingoperation for sewing the second cover material (7) to the first one (4).

As understandable from FIGS. 3 and 4, the movable guide plate (1) isprovided, on the reverse side thereof, with the previously stated threerollers (11)(12)(13), in such a manner that those rollers (11)(12)(13)are disposed at the three points corresponding to three apexes ofequilateral triangle. Further, the same guide plate (1) is provided, onthe upper side thereof, with the following three means for securing thefirst cover material (4) thereupon: a peripheral securing member (14); asecuring needle (15); and a clamp (CL). The peripheral securing member(14) comprises plural small strips of needle cloths (14a) with many thinneedles erected thereon, and a tape of velvet-type fastener (14b) (theso-called magic tape). As shown, the velvet-type fastener tape (14b) isfixed on and along the three peripheral sides (1c)(1a)(1b) of movableguide plate (1), and the needle cloths (14a) are fixed inwardly of thesame guide plate (1), extending abreast with that fastener tape (14b) inthe same length. The securing needle (15) erects on a central pointforwardly of the movable guide plate (1), while on the opposite sidesthereto, the clamp (CL) is fixed on the backward side (1d) of movableguide plate (1). Using those securing elements, the first cover materialcan be precisely located and positively secured on the movable guideplate (1) against unexpected movement during the sewing operation.

Designation (24) in FIG. 1 denotes a cover location wall of a generally"U" shape which projects upright on and extends along the left-sideperipheral end portion of the guide base plate (2), at the side of thecover setting/sewing terminal section (AS). The cover location wall (24)is used in conjunction with the movable guide plate (1) to locate thefirst cover material (4), precisely, with respect to the movable guideplate (1), as will be elaborated later.

Also, designation (25) in FIG. 1 denotes a generally U-shaped cut-awayarea formed in both left-side ends of the cover location wall (24) andguide base plate (21). Through this cut-away area (25), an operator canmake his or her hand accessible to the movable guide plate (1) set onthe left-side half region of guide base plate (2) to take off that guideplate (1) therefrom.

FIG. 8 shows a whole structure of guide base plate (2) on which aparticular guide groove pattern is formed for guiding the three rollers(11)(12)(13) of movable guide plate (1) properly in order to permitautomatic sewing of the second cover material (7) with the first covermaterial (4).

The guide groove pattern, in accordance with the present invention, isthe one collectively formed by the three different guide grooves (21),(22) and (23). Designations (121A), (122A) and (123A) denote therespective guide start points of those three guide grooves (21), (22)and (23) which are defined on the right side of guide base plate (2)corresponding to the sewing start section (BS). Designations (122B),(121B) and (123B) denote the respective guide end points of the threeguide grooves (21), (22) and (23) which are defined on the left side ofguide base plate (2) corresponding to the cover setting/sewing terminalsection (AS).

Reference is now made to FIG. 11, wherein the first guide groove (21) isclarified by the dots. The illustrated meandering or winding irregularpassage of the first guide groove (21) basically includes: a firststraight groove area (21A) leading from the guide start point (121A); asecond generally U-shaped curved groove area (21B) at the arrow (1); athird generally straight groove area (21C); a fourth generally invertedU-shaped curved groove area (21D), at the arrow (2); a fifth inwardlyarcuate groove area (21E); and a sixth outwardly curved groove area(21F), at the arrow (3), which leads to the guide end point (121B). Inoperation, the corresponding first guide roller (11) of movable guideplate (1) follows those groove areas in the directions as indicated bythe three arrows (1)(2)(3), from the guide start point (121A) to theguide end point (121B).

Reference is made to FIG. 12, wherein the second guide groove (22) isclarified by the dots. The groove pattern shown therein is of agenerally reversed shape as compared with the foregoing pattern of firstguide groove (21), but includes the following different groove areas: afirst straight groove area (22A) which is generally equal in length tothe one (21A) of first guide groove (21) and extends in paralleltherewith; a second zigzag groove area (22B), as seen at the arrow (1);a third outwardly arcuate groove area (22C) which extends generally in asymmetrical relation with the fifth arcuate groove area (21E) of thefirst guide groove (22) with respect to the central line of the guidebase plate (2); a fourth generally inverted-U-shaped curved groove area(22D) which crosses the second U-shaped curved groove area (21B) offirst guide groove (21) at two points; a common generally straightgroove area which is the same groove area with the third groove area(21C) of first guide groove (21); and a fifth generally U-shaped curvedgroove area (22E) which crosses the the fourth inverted-U-shaped curvedgroove area (21D) at two points, as seen at the arrow (3). The fifthcurved groove area (22E) leads to the guide end point (122B). Inoperation, the corresponding second guide roller (12) of movable guideplate (1) follows those several groove areas in the directions asindicated by the three arrows (1)(2)(3) from the guide start point(122A) to the guide end point (122B).

Reference is further made to FIG. 13, wherein the third guide groove(23) is clarified by the dots. As can been seen from FIG. 3, a wholepattern of this guide groove (23) is generally of an inverted "Ω" shapeand mostly surrounded by the central, circularly aggregated patternportion of both first and second guide grooves (21)(22). The illustratedgroove pattern is essentially required for permitting the correspondingthird guide roller (13) to move in a non-interference cooperation withthe movements of the first and second guide rollers (11)(12) along theirrespective guide grooves (21)(22), so as to insure smooth displacementof the movable guide plate (1) for sewing together the first and secondcover materials (4)(7). Now, referring to FIG. 8 and FIG. 11, the guidepattern of third guide groove basically includes: a first straightgroove area (23A) generally equal in length to the first straight groovearea (21A) of first guide groove (21); a second generally circulargroove area (23B); and a third groove area (23C) defined at the centralcurved part of second circular groove area (23B). The second circulargroove area (23B) leads to the guide end point (123B). In operation, asindicated by the four arrows (1) (2)(3)(4) in FIG. 13, the correspondingthird guide roller (13) follows those groove areas (23A)(23B) (23C) fromthe guide start point (123A) to the guide end point (123B).

The above-described particular patterns of first, second and third guidegrooves (21)(22)(23) are formed in conformity with the respective threetraces or loci of the first, second and third guide rollers (11)(12)(13)disposed respectively at the three equidistant apexes (of equilateraltriangle).

Here, according to the present invention, the arrangement of those threeguide rollers (11)(12)(13) is such that, referring again to FIG. 3, thefirst guide roller (11) is disposed adjacent to one curved cornerportion (41) of movable guide plate (1) and at the center of circlealong which that curved corner portion (41) extends, the circle thushaving a radius corresponding to the rasius of curvature (R) of thatparticular curved corner portion (41), likewise, the second guide roller(12) is disposed at the center of circle along which another curvedcorner portion (42) extends, the circle therefore also having a radiuscorresponding to the same curvature radius (R) of that another cornerportion (42), and that the third guide roller (13) is disposed at apoint toward which two straight lines intersect, each extending at 60degrees of inclination angle from those two centers of first and secondguide rollers (11)(12), respectively.

We, the inventors, have found that such equilateral triangulararrangement of guide rollers (11)(12)(13) not only suffices to supportstably the movable guide plate (1), but also only requires the twominimum movements: namely, a generally straight movement and a generallycircular movement, in order to cause proper displacements of the movableguide plate (1) for automatical feeding of both first and second covermaterials (4)(7) towards the sewing needle (100) of sewing machine (M),so that the two cover materials (4)(7) may be sewn together along theafore-stated seam (40 or 70) (see FIG. 2) which includes two curvedcorner portions (41)(42). Indeed, the three individual grooves(21)(22)(23) shown in FIGS. 11, 12 and 13 support such inventors'technical discovery, and this groove pattern is most effective in stablyguiding the straight sewing margins of both first and second materials(4)(7) in a direction along the sewing direction (SD) of sewing machine(M) (see FIG. 14), and further stably orienting a tangent touching oneither of the two curved corner portions (41)(42) of the first covermaterial (4) towards the sewing direction (SD) of sewing machine (M), asunderstandable from FIG. 14, for example.

Referring to FIGS. 8, 9 and 10, the sewing device in the presentinvention is provided with an auxiliary means for facilitating smoothturning or directional changes of the first and second guide rollers(11)(12) at their respective acutely curved points where the rollers aremost hard to turn or change their directions. As a preferred meansserving that purpose, there are provided a first auxiliary roller device(230, 211) for the first guide roller (11), and a second auxiliaryroller device (223, 221) for the second guide roller(12). Both first andsecond auxiliary roller devices are each basically comprised of anauxiliary roller assembly (at 230 or 223) and a cylinder (211 or 221),and of the same mechanical structure. With particular reference to FIG.8, the cylinder (211) of the first auxiliary roller device iselectrically connected with a first guide sensor (301) situated in theleft-side curved part of second circular groove area (23B) of the thirdguide groove (23), whereas likewise, the cylinder (221) of the secondauxiliary roller is electrically connected with a second guide sensor(302) situated in the central curved part of the same second groove area(23), adjacent to the left-side juncture of third curved groove area(23C). Upon one of the two sensors (301 or 302) detecting the thirdguide roller (13), it is turned on to energize the corresponding one ofthe cylinders (211 or 221) so as to to move forwardly the correspondingauxiliary roller assembly (at 230 or 223).

Now, a specific description will be made only in regard to the secondauxiliary roller device (223, 221), for the sake of simplicity ofdescription. As shown in FIGS. 9 and 10, the second auxiliary rollerdevice comprises the afore-said cylinder (221) having a cylinder rod(221A), and an auxilliary roller assembly consisting essentially of: agenerally inverted-L-shaped cross-section of guide rail member (227)which, as best seen in FIG. 10, has an upwardly extending part fixed tothe reverse side of guide base plate (2) and a horizontally extendingpart, with a guide slit defined between the guide base plate reverseside and that horizontally extending part, wherein the horizontallyextending part has an auxiliary guide groove (227A) perforated therein,which extends along and in parallel with the third curved groove area(22C) of second guide groove (22); a slide member (222) slidably fittedin the foregoing guide slit of the guide rail member (227); a mainauxiliary roller (223) rotatably mounted on the upper end of a shaft(223a) fixed in the slide member (222), wherein the shaft (223a)penetrates through the slide member (222), passes through the auxiliaryguide groove (227A) and terminates in a lower threaded end to which oneend of a generally L-shaped bracket (226) is firmly connected by meansof a nut, wherein another end of the bracket (226) is firmly connectedto the piston rod (221A) of cylinder (221) by means of a nut; a lowersub roller (225) fixed to the reverse side of slide member (222), thelower sub roller (225) being rotatably fitted in the auxiliary guidegroove (227A); and an upper sub roller (224) fixed on the upper side ofslide member (22), the upper sub roller (224) being normally located, asshown, in a recessed portion (2a) formed in the reverse side of movableguide plate (2). The recessed portion (2a) communicates with the thirdcurved groove area (22C) of second guide groove (22). The upper andlower sub rollers (224)(225) are disposed on the opposite sides of themain auxiliary roller (223). With this construction, operation of thecylinder (221) causes all the slider member (222), main auxiliary roller(223), upper and lower sub rollers (224)(225) to be moved forwardly inthe arrow direction in FIG. 9 so as to push the corresponding secondguide roller (12) along the third curved groove area (22c), as will beelaborated later. The same operation is to be made in the firstauxiliary roller device (211, 230) for pushing the corresponding firstguide roller (11) along the fifth curved groove area (21E) of firstguide groove (21), which also will be elaborated later.

Designations (401) and (402) represent a first deceleration microswitchand a second deceleration microswitch, respectively. Both microswitches(401)(402) are electrically connected with the computerized controlsection (M1) for decreasing the feeding or sewing speed of the sewingmachine (M), when the third guide roller (13) reaches and turned on eachof those two microswitches. As viewed from FIG. 8, the firstdeceleration microswitch (401) is disposed at the left-side curved partof the second circular groove area (23B) of third guide groove (23) andsituated before the above-stated first sensor (301), and the seconddeceleration microswitch (402) is disposed at the left-side end orjuncture of third curved groove area (23c) which communicates with thecentral curved part of second circular groove area (23B).

Designation (403) in FIG. 8 stands for a sensor or microswitch foroperation of the auxiliary guide device (3A). The sensor (403) iselectrically connected with the auxiliary guide device (3A) via thecontrol section (M1).

Now, a description will be made of specific operations of theabove-constructed automated sewing device.

Firstly, as shown in FIG. 5, an operator should set the movable guideplate (1) on the left-side half cover-setting/sewing terminal section(AS) of guide base plate (2) by fitting the three guide (11)(12)(13)into their respective initial setting points (122C)(121C) (123C). Asunderstandable from FIG. 8 and FIG. 5, the three initial setting points(122C) (121C)(123C) are defined in the respective terminal ends of thethree guide grooves (21)(22)(23). Therefore, the movable guide plate (1)can be set at the three points and located precisely with respect to thelocation wall (24) of guide base plate (2), with a predetermined widthof clearance (c) provided between the three peripheral sides (1a, 1b,and 1c. See FIG. 3) of the movable guide plate (1) and the three wallsections (24a, 24b, 24c) of the location wall. The clearances (c) have agiven width corresponding to the aforementioned sewing margin (e.g. 10mm) of both first and second cover materials (4)(7). It is noted that,for that reason, the location wall (24) should have two greater curvedcorner portions (24b-1)(24c-1), each having a proper greater radius ofcurvature than that (R) each of the corresponding two curved cornerportions (101)(102) of movable guide plate (1) (see FIG. 3, therebyproviding those clearances (c).

In the preset embodiment, though not shown, both first and second covermaterials (4)(7) are each of a three-layer lamination type comprising atop cover layer (e.g. a leather), a foam padding layer (of urethane foammaterial) and a back cloth layer.

Secondly, the operator should take the first cover material (4), as itshows its top cover layer upwardly, then bring its forward central edgeand two corner portions (41)(42) into contact and alignment with theinward wall surfaces of the corresponding three wall sections (24a)(24b-1)(24c-1) of location wall (24), and have the securing needle (15)of movable guide plate (1) pierced through that first cover material(4), then laying down the remaining part of same cover material (4) onthe movable guide plate (1) as can be seen in FIG. 6. After beingfinally secured its backward end side by the clamp (CL), the first covermaterial (4) is precisely located in a given position upon the movableguide plate (1). Then, all the peripheral ends, excepting the backwardend, of the first cover material (4) are removably secured to and alongboth needle needle cloths (14a) and velvet-type fastener (14b) of themovable guide plate (1), manually by the hands of the operator, therebycompleting the provisional securement of first cover material (4) on themovable plate (1) as in FIG. 6 and 7.

Next, the operator should grasp, with his or her hand, the left-side endof the thus-combined unit of both first cover material and movable guideplate, though the cut-away area (24), as in FIG. 6, and take out it fromthe guide base plate (2).

The thus-removed movable guide plate (1) with the first cover material(4) secured thereon should then be brought towards the right-side sewingstart section (BS) of the guide base plate (2), and set thereon byfitting the three guide rollers (11)(12)(13) into the start end points(121A)(122A)(123A), respectively, as indicated by the dot and one-dotchain lines in FIG. 8. At this moment, the sewing start point (40A) offirst cove material (4) (see FIG. 2) is positioned just under the sewingneedle (100) of sewing machine (M).

Then, the operator should take another second cover material (7), andplace the same (which also shows its top cover layer upwardly) upon thestationary guide plate (3), passing one forward end portion of thatsecond cover material (7) between the guide plate (3) and guideintroductory plate (3A-2) of auxiliary guide device (3A) towards thesewing needle (100), and then juxtapose such one forward end portion ofsecond cover material (7) upon the portion of first cover material (4)where its sewing start point (40A) exists, such as to coincide thesewing start point (40A) of second cover material (7) with that point(40A) within the given sewing margin.

Thereafter, operating the sewing machine (M) starts movements of itssewing needle (100) and feeding member (101) to automatically draw bothfirst and second cover materials (4)(7) and sew then together, while themovable guide plate (1) is caused by the feeding force of sewing machine(100) to be moved along the three straight guide groove areas(21A)(22A)(23A).

FIG. 14 shows the state where one lateral side portion each of bothfirst and second cover materials (4)(7) are sewn together. Although notshown, up to this sewing stage, the first and second guide rollers(11)(12) have passed along or followed their corresponding firststraight groove areas (21A)(22A) and second curved groove areas(21B)(22B), while the third guide roller (13) has followed itscorresponding first straight groove area (23A) and the gently curvedpart of the second circular groove area (23B) (which is, howeverstrictly stated, of a generally elliptical shape as shown), to therebycause proper displacement of the movable plate (1) for completing thesewing together of those first lateral side portions of both first andsecond cover materials (4)(7) which includes a gently curved, slopedarea (sl), as understandable from the phantom lines in FIG. 14. But, theFIG. 14 itself also indicates that the second cover material (7) isabout to be sewn along one curved corner portion (42) of first covermaterial (4). At this point, the first guide roller (11) follows thegenerally straight third groove area (21C), while the second guideroller (12) is positioned at the most acutely curved point or juncturebetween the second and third groove areas (22B)(22C), i.e. the pointwhere the roller (12) is most difficult to turn or change its direction.However, since the third guide roller (13) passes the left-side curvedpart of the second circular or elliptical groove area (23B) during thishardest change of direction, the first deceleration microswitch (401) isturned "on" by that third guide roller (13) to decrease the sewing orfeeding speed of sewing machine (M), thus allowing the second guideroller (12) to slowly enter the third groove area (22C) from the secondgroove area (22B), soon after which, the third guide roller (13) furtherpasses by the first guide sensor (301), which then detect it andenergizes the cylinder (221) to move forwardly the auxiliary roller(223), with the result that the auxiliary roller (223) collides againstthe second guide roller (12) and pushes the same in a direction alongthe third arcuate groove area (22C). Namely, the second guide roller(12) is given an additional force enough to turn at the most acutelycurved point, and smoothly passes therethrough for further followingalong the third guide groove area (22C). Also, at this moment, thesensor (403) is turned "on" by that third guide roller (13), whichresults in the auxiliary guide device (3A) being operated to to bringits roller (3A-1) to contact with the second cover material through theopening (3A-2a) so as to upturn that particular second cover material(7) from the sewing line between it and the first cover material (4)along the first curved corner portion (42) of the latter (see thephantom lines in FIGS. 15, 16 and 17).

The slow down time of the sewing machine (M) caused by the decelerationmicroswitch (401) is preset in the control section (M1) for anappropriate time period that allows the sewing mcahine (M) to sew mostof both first curved corner portions of first and second cover materials(4)(7), so that after lapse of such time, the sewing or feeding speed ofsewing machine (M) is returned to the previous normal one. Though notshown, this process may be programmed, using a known computerizedelectric circuitry in the control section (M1).

FIG. 15 shows the state where the first curved corner portion (42) offirst cover material (4) has been sewn with the corresponding curvedcorner portion of second cover material (7) and the forward rectilinearend portion of the same cover material (4) is being sewn with thecorresponding end portion of second one (7). Up to this sewing stage,though not shown clearly but as understandable from the solid-line anddot-line arrows in both FIGS. 14 and 15, the second guide roller (12)has passed along or followed its corresponding third and fourth curvedgroove areas (22C)(22D), while the second guide roller (12) has followedthe left-side end and central parts of second elliptical groove area(23B) as well as the midway in the third curved (or generallyinverted-U-shaped) groove area (23C) (see FIG. 15). During this stage,the first guide roller (11), by contrast, is almost stopped at themidway of generally straight groove area (21C) which corresponds to thesewing needle (100). In other words, because of the two non-acutelyarcuate guiding passages defined respectively by those particular grooveareas (22C)(23B), and further because of the center of the first guideroller (11) being positioned adjacent to and in correspondence with theaxis of sewing needle (100), the points to be applied greater by thefeeding force of sewing machine (M) in such equilateral-triangle guideroller arrangement are the second and third guide rollers (12)(13) thanthe first guide roller (11). This allows the first guide roller (11) tobe substantially retained against movement at the center of a circularalong which the curved corner portion (42) of first cover material (4)extends, while at the same time allowing the second and third guiderollers (12)(13) to be displaced in an arcuate way with respect to thatfirst guide roller (11), which effectively insures to orient the firstand second cover materials (4)(7) towards the sewing needle (100) in thetangential direction thereof to complete sewing them together along thecurvature of their common corner portions (i.e. at (42)). The same goesfor the case of sewing the corner portion (42) of one first covermaterial (4) only. It is also observed that the second cover material(7) is upturned from the peripheral sides of first cover material (4)during the sewing operation.

FIG. 16 shows the state where the second cover material (7) is about tobe sewn along another curved corner portion (41) of first cover material(4). At this point, the second guide roller (12) follows the generallystraight third groove (21C), while the first guide roller (11) ispositioned at another most acutely curved point or juncture between theforth and fifth arcuate groove areas (22D)(22E), i.e. the point wherethe roller (11) is most difficult to turn or change its direction. But,as the third guide roller (13) passes along the left-side juncturebetween the second and third groove areas (23B)(23C) (as viewed from theFIG. 16), the second deceleration microswitch (402) located there (seeFIG. 8) is turned "on" by that guide roller (13) to decrease the sewingor feeding speed of sewing machine (M), thus allowing the first guideroller (11) to slowly enter the fifth groove area (22E) from the fourthgroove area (22D), soon after which, the third guide sensor (302), whichis located generally at the central part of the second elliptical secondgroove area (23B) (23B) in the proximity of that decelerationmicroswitch (402), detects the third guide roller (13) and energizes thecylinder (221) to move forwardly the auxiliary guide roller (230). As aresult, the auxiliary roller (230) collides against and pushes the firstguide roller (11) in a direction along the fifth groove area (21E), thusgiving the roller (11) an additional force enough to turn at the mostacutely curved point and allowing it to pass smoothly therethrough forfurther following along the fifth groove area (21E). Although notclearly shown, but as understandable from the solid-line and dot-linearrows in FIG. 16, as similar to the above-explained turning motions inFIG. 14, the second guide roller (12) is substantially retained againstmovement at the midway of generally straight groove area (21C)corresponding to the sewing needle (100), i.e. the center of a circlealong which the second curved corner portion (41) extends, while on theother hand, the first guide roller (11) follows the fourth and fifthgroove areas (21D)(21E) and the third guide roller (13) follows thethird groove area (23C) and the remaining passage of the second groovearea (23B), as indicated by the arrow in FIG. 6 and arrow (4) in FIG.13. Namely, the first and third guide rollers (12)(13) are displaced inan arcuate way relative to the second guide roller (12), and because ofthe second guide roller (12) being at the center of a circle along whichthe second curved corner portion (42) of first cover material (4)extends, such particular turning motions of the former two rollers(11)(13) about the substantially suspended latter roller (12) insures tocause both cover materials (4)(7) to be sewn together along thecurvature of their common corner portions (i.e. at (41)) by the sewingmachine (M).

Thereafter, although not shown but as understandable from FIGS. 11, 12,13 and 16, the first guide roller (11) follows the sixth curved groovearea (21F) to reach the end point (121B) as indicated by the arrow (3)in FIG. 11, the second guide roller (12) follows the fifth curved groovearea (22E) to reach the end point (122B) as indicated by the arrow (3)in FIG. 12, and the third guide roller (13) follows the remaining part(generally straight part) continuous from the second circular groovearea (23B) to reach the end point (123B) as indicated by the arrow (4)in FIG. 13, so as to complete sewing together the another lateral sideof the both first and second cover materials (4)(7). Though not shown,the three end points (121B)(122B)(123B) are each provided with amicroswitch connected electrically with the control section (M1). Thus,upon all those three guide rollers (11)(12)(13) reaching their endpoints (121B)(122B)(123B), the microswitch is turned "on" to send asignal to the control section (M1) which discontinues the supply ofcurrent to the sewing machine (M), whereupon the sewing machine (M) andauxiliary guide device (3A) are stopped to finalize the sewing of thefirst and second cover materials (4)(7) at their respectivepredetermined sewing end points (40B)(70B). Consequently, the firstcover material (4) with the second cover material (7) erected from andalong the three sides thereof is produced, and should be removed fromthe movable guide plate (1). (In this respect, again, the same processesmay be executed in the case of sewing only one first cover material(4).) Then, the upturned second cover material (7), which shows itsreverse side outwardly along the three peripheral sides of the firstcover material (4), is turned over relative to that first one (4) so asto produce such three-dimensional trim cover assembly as shown in FIG.17.

It is noted that the second slow down time of sewing machine (M) causedby the second deceleration microswitch (402) is also preset as likewisein the first one (401) mentioned above, so that the sewing machine (M)may be worked slowly during the step of sewing the second corner portion(41) of first material and after lapse of the preset time, its sewing orfeeding speed be returned to the normal faster speed.

The illustrated guide groove pattern formed on the guide base plate (2)is adapted to cause the above-described displacements of movable guideplate (1) for sewing the generally U-shaped three peripheral sides offirst cover material (4) or of both first and second cover materials(4)(7) which is of the type including such four curved corner portions(sl, 41, 42), and strictly stated, the whole peripheral U-shaped threesides thereof is slightly close to a circular shape. However, thegeneric technical concept of the present invention resides in using theabove-elaborated equilateral-triangular guide roller arrangement toattain the sewing of such generally U-shaped cover material, be it oneor two cover materials, which includes two curved corner portions.Hence, the guide groove pattern of guide base plate (2) per se may bemodified slightly from the illustrated one, depending on minor partialchanges of seat design, but even in that case, the basic formation ofgenerally straight guide groove areas (e.g. 21A, 22A, . . . ) andgenerally dual circular or elliptical guide groove areas (e.g. 22C, 21C,21E and 23B, 23C . . . ) is a basic criteria for forming a specificshape of whole guide groove pattern, depending on a minor partial designof either one or two cover materials. For instance, if the first andsecond cover materials (4)(7) are not formed with such minor curvedportions (at sl), the curved groove areas (21B, 22B, 21F, 22E) are notdefined in the whole groove pattern, while the third guide groove (23)shows more smooth elliptical configuration in its second groove area(23B), so that more simple straight and curved or circular basic grooveformation may be formed than the illustrated one.

Further, in the illustrated embodiments, preferably, during theforegoing sewing operations, the decorative beading may be sewn togetherwith the first and second cover materials (4)(7) by operation of thepreviously stated device (5, 6) for fixing a decorative beading, so thatthe beading extends integrally along the sewn line between both covermaterials (4)(7) for improvement of aesthetic appearance of resultingtrim cover assembly.

While having described the present invention thus far, it should beunderstood that the invention is not limited to the illustratedembodiments, but other various modifications, replacements and additionsmay be structurally applied thereto without departing from the scopes ofthe appended claims.

What is claimed is:
 1. An automated sewing device for sewing a basematerial with a pair of first and second curved corner portions formedin at least one side thereof, each having a same radius of curvature,said automated sewing device comprising:a sewing machine including asewing needle and a feeding member; a movable guide means having a shapegenerally similar to that of said base material, upon which movableguide means, said base material is to be secured; said movable guidemeans being provided, on a reverse side thereof, with a first guideroller, a second guide roller and a third guide roller, in such a mannerthat said first and second guide rollers are respectively disposed atone point corresponding to a center of curvature of said first curvedcorner portion of said base material and at another point correspondingto a center of curvature of said second curved corner portion of thesame base material, and further that all said first, second and thirdguide rollers are disposed at three apexes of an equilateral triangle,respectively; a base guide plate means in which a plurality of guidegrooves are formed in such a pattern that describes three locirespectively of said first, second and third guide rollers required tocause proper displacements of said movable guide means for guiding saidat least one side of said base material including said first and secondcurved corner portions in a direction to said sewing needle of saidsewing machine, wherein, upon said base guide plate means, said movableguide means is movably mounted, with said first, second and third guiderollers being slidably fitted in said plurality of guide grooves,wherein said at least one side of the base material secured on themovable guide means is automatically fed and sewn by said sewingmachine, with said movable guide means being displaced under guidance ofsaid first, second and third guide rollers which follow the respectivesaid three loci.
 2. The automated sewing device according to claim 1,wherein said plurality of guide grooves include one acutely curvedgroove portion where said first guide roller resists a change indirection thereof, and another acutely curved groove portion where saidsecond guide roller resists a change in direction thereof, and wherein afirst auxiliary guide roller means is provided to facilitate directionalchange of said first guide roller along said one acutely curved grooveportion, and a second auxiliary guide roller means is provided tofacilitate directional change of said second guide roller along saidanother acutely curved groove portion.
 3. The automated sewing deviceaccording to claim 2, wherein each of said first and second auxiliaryguide roller means comprises a guide slit defined along a part of eitherof said one and another acutely curved groove portions, an auxiliaryguide roller slidably fitted in said guide slit, and a cylinderconnected to said auxiliary guide roller, and wherein operation of saidcylinder causes said auxiliary guide roller to move along said guideslit, pushing each of said first and second guide rollers to facilitatedirectional change thereof at the corresponding one of said one andanother acutely curved groove portions.
 4. The automated sewing deviceaccording to claim 3, wherein a sensor means is provided in associationwith each of said first and second auxiliary guide roller means, saidsensor means being disposed at a portion of said guide grooves whichsaid third guide roller follows, at a point of time when one of saidfirst and second rollers reaches the corresponding one of said one andanother acutely curved groove portions, so that said sensor means maydetect said third guide roller to actuate one of said first and secondauxiliary guide roller means.
 5. The automated sewing device accordingto claim 1, wherein a speed control means is provided for decreasing asewing or feeding speed of said sewing machine, only during a time whenone of said first and second rollers change its direction at acorresponding acutely curved groove portion in said guide grooves wheresaid one of said first and second rollers resists a change in itsdirection thereof.
 6. The automated sewing device according to claim 5,wherein a switch means is provided in association with said speedcontrol means, said switch means being disposed at a portion of saidguide grooves which said third guide roller follows at a point of timewhen one of said first and second rollers reaches the correspondingacutely curved groove portion, so that said switch means may be turnedon by said third guide roller to decrease said sewing or feeding speedof said sewing machine.
 7. The automated sewing device according toclaim 1, wherein said plurality of guide grooves include generallystraight groove areas, curved groove areas and generally circular grooveareas, which are formed in conformity with said three loci respectivelyof said first, second and third guide rollers required to cause saidproper displacements of said movable guide means for guiding said atleast one side of said base material including said first and secondcurved corner portions in a direction to said sewing needle of saidsewing machine, such that said first, second and third guide rollers mayfollow said generally straight groove areas to cause a generallystraight side portion of said base material to be sewn by said sewingneedle along a sewing direction thereof, and then one of said first andsecond guide rollers may follow said curved groove areas in cooperationwith said third guide roller following said generally circular grooveareas so as to cause one of said first and second curved corner portionsof said base material to be sewn by said sewing needle along a curvaturethereof, after which, another of said first and second guide rollers mayfollow said curved groove areas in cooperation with said third guideroller following said generally circular groove areas so as to causeanother of said first and second corner portions of said base mateial tobe sewn by said sewing needle along a curvature thereof.
 8. Theautomated sewing device according to claim 7, wherein both said curvedand generally circular groove areas are defined centrally of saidmovable guide means, such that said circular groove areas are disposedinwardly of said curved groove areas, and said straight groove areas aredefined on opposite sides of those curved and generally circular grooveareas, so that said first, second and third guide rollers may followsaid straight groove areas along their respective loci to cause sewingof said generally straight side portion of said base material, at eachof sewing start and sewing end points on said movable guide means, andthat said first and second guide rollers may follow said curved grooveareas along their respective said loci, while said third guide rollermay follow said generally circular groove areas along the locus thereof,without interference among those three guide rollers, to cause each ofsaid first and second curved corner portions of said base material to besewn along the curvature thereof by said sewing needle.
 9. The automatedsewing device according to claim 8, wherein said generally straightgroove areas include a common groove portion disposed near said sewingneedle, while said curved groove areas include first and second curvedgroove portions which are distant from said sewing needle and disposedgenerally in a symmetrical relation with each other relative to saidsewing needle, an arrangement of those common, first and second curvedgroove portions being such that when sewing said first curved cornerportion of said base material, said second and third guide rollers aredisplaced in a generally arcuate way with respect to said first guideroller being positioned at said common groove portion, thereby causingsaid first curved corner portion to be sewn by said sewing needle in adirection of tangent touching on the curvature of said first curvedcorner portion, and that when sewing said second curved corner portionof said base material, said first and third guide rollers are alsodisplaced in a generally arcuate way with respect to said second guideroller being positioned at said common groove portion, thereby causingsaid second curved corner portion to be sewn by said sewing needle in adirection of a tangent touching on the curvature of the said secondcurved corner portion.
 10. The automated sewing device according toclaim 1, wherein said movable guide means is provided, at an uppersurface thereof, with a securing means for locating and removablysecuring said base material upon said movable guide means, and whereinsaid securing means comprises a peripheral securing element disposedalong a peripheral side of said movable guide means, and a securingneedle disposed generally centrally of said movable guide means.
 11. Theautomated sewing device according to claim 1, wherein said peripheralsecuring element comprises a plurality of needle cloths and avelvet-type fastener type for removably securing peripheral end portionsof said base material on said movable guide means.
 12. The automatedsewing device according to claim 1, wherein said movable guide means isa movable guide plate formed in a shape generally similar to that ofsaid base material, which is provided, at a reverse surface thereof,with said first, second and third guide rollers, and further provided,at an upper surface thereof, with a securing means for securing saidbase material thereon, said movable guide plate having at least one sidewhich includes two curved corner portions generally similar to those ofsaid at least one side of said base material, wherein said at least oneside of said base material is to be located and secured on said at leastone side of said movable guide plate via said securing means, andwherein said base guide plate means includes a location wall erected atone end side thereof, said location wall being formed in a shapegenerally similar to said at least one side of said movable guide plate,so that said said movable guide plate may be set on said base guideplate in reference to said location wall and thereafter, said basematerial may be precisely located in a given position upon said baseguide plate by bringing said at least one side of said base material tocontact and alignment with said location wall.
 13. The automated sewingdevice according to claim 12, wherein said base guide groove is formedwith three additional grooves each terminating in a setting end in whicheach of said first, second and third guide rollers is to be fitted,respectively, in order to insure location of said movable guide plate inreference to said location wall.
 14. The automated sewing deviceaccording to claim 12, wherein said base guide plate means includes acut-away portion at said one end side thereof, said cut-away portionbeing formed in both said base guide plate means and location wall, andbeing adapted to make accessible an operator's hand therethrough to saidmovable guide plate which is set on said base guide plate in referenceto said location wall.
 15. The automated sewing device according toclaim 1, wherein a stationary guide plate is provided above said movableguide means, so that another base material may be introduced on saidstationary guide plate towards said sewing machine, and then a part ofsaid another base material may be sewn with and along said at least oneside of said first base material which is secured on said movable guidemeans.
 16. The automated sewing device according to claim 15, whereinsaid stationary guide plate has an auxiliary guide device providedtherewith, and wherein said auxiliary guide device is operable to upturnsaid part of said another base material from said first base materialduring sewing operation of said sewing machine.
 17. The automated sewingdevice according to claim 1, wherein said base material is of athree-layer lamination type comprising a top cover layer, a foam paddinglayer and a back cloth in this order.